Hey Big Jib,
No issues with castings, ever, but I have gone through several sets of 20 blades. That was the whole reason for looking to an alternative that sailed well, and was more bullet proof. I am a big guy, and I sailed the north americans with a big crew, together on the boat we were 480 lbs or so. Considering that we were traveling down to the hiking strap at times and still fully powered up, there was a great deal of load on the entire boat. We were fast in the windy conditions, at least up wind, but I am sure that we would have been faster with the EPO2s. The only part to show signs of failure was the rudder.
I have sailed the EPO2s in just as much wind and more rough seas and the rudders don't show any signs of failure. The stock 20 blades now flex like the plastic H-16 blades. The EPO2s are stiff. Stiff is fast.
Looking for a Holiday gift from santa? A nice set of EPO2s would be really nice, trust me.
By the way, drilling the EPO2s was a little bit of a trick. Line up the blades to keep the tips of the blades equal and the leading edge of the EPO2 in line with where the stock 20 blade hits the lower part of the lower casting. This pulls the center of load forward (you loose some of the trailing edge of the stock blade) so this may allow some adjustability with the new rudders. On my boat, it made the helm more balenced. I used the old rudders as a guide to drill the lower/front hole and marked the upper/back hole. I then used the upper casting in the full lock down position as a drill guide. This is a two person job as someone needs to stand back and sight the drilling angle and help to hold the casting in place. The mark I made was close, but this method made it really work better. One last note, make sure you check the swing of the castings in both positions prior to drilling anything. Measure twice, drill once.